Isaiah 35:3

The prophet now exclaims to the afflicted church, in language of unmixed consolation, that Jehovah is coming. "Strengthen ye the weak hands, and make the trembling knees strong! Say to those of a terrified heart, Be strong! Fear ye not! Behold, your God will come for vengeance, for a divine retribution: He will come, and bring you salvation." Those who have become weak in faith, hopeless and despairing, are to cheer up; and the stronger are to tell such of their brethren as are perplexed and timid, to be comforted now: for Jehovah is coming nâqâm (i.e., as vengeance), and gemūl 'Elōhı̄m (i.e., as retribution, such as God the highly exalted and Almighty Judge inflicts; the expression is similar to that in Isa 30:27; Isa 13:9, cf., Isa 40:10, but a bolder one; the words in apposition stand as abbreviations of final clauses). The infliction of punishment is the immediate object of His coming, but the ultimate object is the salvation of His people (וישעכם a contracted future form, which is generally confined to the aorist).

As after a prediction of God's judgments upon the world (ch. 24) follows a promise of great mercy to be had in store for his church (Isa 25:1-12), so here after a black and dreadful scene of confusion in the foregoing chapter we have, in this, a bright and pleasant one, which, though it foretel the flourishing estate of Hezekiah's kingdom in the latter part of his reign, yet surely looks as far beyond that as the prophecy in the foregoing chapter does beyond the destruction of the Edomites; both were typical, and it concerns us most to look at those things which they were typical of, the kingdom of Christ and the kingdom of heaven. When the world, which lies in wickedness, shall be laid in ruins, and the Jewish church, which persisted in infidelity, shall become a desolation, then the gospel church shall be set up and made to flourish. I. The Gentiles shall be brought into it (Isa 35:1, Isa 35:2, Isa 35:7). II. The well-wishers to it, who were weak and timorous, shall be encouraged (Isa 35:3, Isa 35:4). III. Miracles shall be wrought both on the souls and on the bodies of men (Isa 35:5, Isa 35:6). IV. The gospel church shall be conducted in the way of holiness (Isa 35:8, Isa 35:9). V. It shall be brought at last to endless joys (Isa 35:10). Thus do we find more of Christ and heaven in this chapter than one would have expected in the Old Testament.

35:3 Tired hands and weak knees express discouragement and anxiety (see Heb 12:12).